This invention relates to a rigging method and hook therefor, particularly for the logging industry.
The invention can be best illustrated by its application to high lead rigging. This embodies a skyline equipped with a traveling carriage. The general environment can be seen in U.S. Pat. No. 4,347,938.
There have been two basic ways of securing logs to the carriage for movement up an incline. One embodies a plurality of chains which depend from the carriage with the lower end of each chain being equipped with a butt hook such as a McGovern butt hook which has been used for upwards of 40 years. Each McGovern hook receives one ferrule-equipped end of a choker line with the other end of the choker line being wrapped around the log and secured to the line by a choker hook. This latter arrangement can be seen in co-owned U.S. Pat. No. 2,872,716.
The other method of securing logs to the carriage involves a single wire rope line which depends from the carriage (called a "drop line") on which are slidably mounted a plurality of bunching hooks such as those seen in co-owned U.S. Pat. No. 3,276,809. Each bunching hook, in turn, receives one ferrule-equipped end of a choker line with the other end of the choker line being wrapped around the log--again as just described above. This second arrangement has become much more prevalent than the first primarily because it permits the accumulating or bunching of the drop line hooks on a single line which makes for economies in cost and operation. However, both of these costs are proving excessive and the operation itself has been characterized by a number of disadvantages.
Two significant disadvantages reside in the difficulty of attaching the choker line to the bunching hook when the upward movement phase of the operation is to be commenced, and later the pendency of the choker lines to become detached from the bunching hooks when they are being returned downhill for another cycle.
Complicating the operation and contributing to the slowness and therefore inefficiency of the cycling was the fact that the loggers were fighting brushy hillsides, deep snow, buried logs and tangled chokers.